1. Field of the Invention
The present invention relates to a power transmission device.
2. Description of the Related Art
As a power transmission device which transmits a driving force output from an actuator to a load member, such as a power transmission device for a joint drive mechanism of a robot, for example, one which has a spring or other elastic member disposed on its power transmission path is conventionally known (for example, see Japanese Patent No. 4107208 (hereinafter, referred to as “Patent Literature 1”)).
In the power transmission device of this type, the fluctuations of the external force acting on the load side can be absorbed by elastic deformation of the elastic member. This can increase the flexibility of the power transmission device and also prevent the power transmission device from being damaged by unexpected fluctuations of the external force and the like.
Further, Japanese Examined Patent Application Publication No. 63-040981 (hereinafter, referred to as “Patent Literature 2”), for example, proposes a worm reduction gear in which the outer periphery of the worm to be meshed with the worm wheel is configured of a coil spring so as to prevent vibrations and noises.